The dynamics of designed short polyisoprene (PI) chains in the melt is investigated on a wide temperature window using dielectric relaxation spectroscopy and pulsed field gradient nuclear magnetic resonance (NMR). At high temperatures, molecular dynamics (MD) simulations performed using two different models (an explicit atom model and a united atom one) capture very well the dynamic properties documented experimentally. Structures pre-equilibrated with end-bridging Monte Carlo are used as initial configurations for MD runs at different temperatures, providing predictions for the temperature dependence of the dynamics of this bulk PI. Local dynamics is unique, independently of the probe (dielectric relaxation, dynamic light scattering, nuclear magnetic resonance, neutron scattering), although mean correlation times are significantly affected, to different extents, by librations. Chain dynamics over the molecular weight and temperature range studied can be described well by the Rouse model, as shown by both experimental data and a normal mode analysis on simulation trajectories. Deviations from the Rouse model emerge for the high modes at short times; still, this model offers a rather accurate picture.

1.
(a)
K.
Adachi
and
T.
Kotaka
,
Macromolecules
17
,
120
(
1984
);
(b)
K.
Adachi
and
T.
Kotaka
,
Macromolecules
18
,
466
(
1985
);
(c)
K.
Adachi
and
T.
Kotaka
,
Macromolecules
21
,
157
(
1988
);
(d)
K.
Adachi
,
H.
Yoshida
,
F.
Fukui
, and
T.
Kotaka
,
Macromolecules
23
,
3138
(
1990
);
(e)
Y.
Imanishi
,
K.
Adachi
, and
T.
Kotaka
,
J. Chem. Phys.
89
,
7585
(
1988
);
(f)
D.
Boese
and
F.
Kremer
,
Macromolecules
23
,
829
(
1990
);
(g)
A.
Schönhals
,
Macromolecules
26
,
1309
(
1993
).
2.
C. M.
Roland
and
K. L.
Ngai
,
Macromolecules
24
,
5315
(
1991
).
3.
(a)
R.
Dejean de la Batie
,
F.
Lauprêtre
, and
L.
Monnerie
,
Macromolecules
22
,
122
(
1989
);
(b)
J.
Denault
and
J.
Prud’homme
,
Macromolecules
22
,
1307
(
1989
);
(c)
B.
Min
,
X.
Qiu
,
M. D.
Ediger
,
M.
Pitsikalis
, and
N.
Hadjichristidis
,
Macromolecules
34
,
4466
(
2001
).
4.
(a)
R.
Zorn
,
D.
Richter
,
B.
Farago
,
B.
Frick
,
F.
Kremer
,
U.
Kirst
, and
L. J.
Fetters
,
Physica B
180 & 181
,
534
(
1992
);
(b)
B.
Frick
and
L. J.
Fetters
,
Macromolecules
27
,
974
(
1994
).
5.
(a)
N. E.
Moe
and
M. D.
Ediger
,
Macromolecules
29
,
5484
(
1996
);
(b)
N. E.
Moe
and
M. D.
Ediger
,
Polymer
37
,
1787
(
1996
);
(c)
N. E.
Moe
and
M. D.
Ediger
,
Phys. Rev. E
59
,
623
(
1999
);
(d)
M.
Fukuda
and
H.
Kikuchi
,
J. Chem. Phys.
113
,
4433
(
2000
);
(e)
J.
Colmenero
,
F.
Alvarez
, and
A.
Arbe
,
Phys. Rev. E
65
,
041804
(
2002
).
6.
(a)
V. A.
Harmandaris
,
M.
Doxastakis
,
V. G.
Mavrantzas
, and
D. N.
Theodorou
,
J. Chem. Phys.
116
,
436
(
2002
);
(b)
M.
Doxastakis
,
V. G.
Mavrantzas
, and
D. N.
Theodorou
,
J. Chem. Phys.
115
,
11339
(
2001
);
(c)
M.
Doxastakis
,
V. G.
Mavrantzas
, and
D. N.
Theodorou
,
J. Chem. Phys.
115
,
11352
(
2001
).
7.
(a)
M.
Doxastakis
,
M.
Kitsiou
,
G.
Fytas
,
D. N.
Theodorou
,
N.
Hadjichristidis
,
G.
Meier
, and
B.
Frick
,
J. Chem. Phys.
112
,
8687
(
2000
);
(b)
M.
Doxastakis
,
K.
Chrissopoulou
,
A.
Aouadi
,
B.
Frick
,
T. P.
Lodge
, and
G.
Fytas
,
J. Chem. Phys.
116
,
4707
(
2002
).
8.
Accelrys URL http://www.accelrys.com/cerius2/
9.
H.
Sun
,
J. Phys. Chem. B
102
,
7338
(
1998
).
10.
F.
Müller-Plathe
,
Comput. Phys. Commun.
78
,
77
(
1994
).
11.
N. E.
Moe
,
XiaoHua
Qiu
, and
M. D.
Ediger
,
Macromolecules
33
,
2145
(
2000
).
12.
J. Higgins and H. Benoit, Polymers and Neutron Scattering (Clarendon, Oxford, 1994).
13.
(a)
P. E.
Rouse
,
J. Chem. Phys.
21
,
1272
(
1963
);
(b) M. Doi and S. F. Edwards, The Theory of Polymer Dynamics (Clarendon, Oxford, 1986).
14.
(a)
G.
Williams
,
D. C.
Watts
,
S. B.
Dev
, and
A. M.
North
,
Trans. Faraday Soc.
67
,
1323
(
1971
);
(b)
E.
Saiz
,
E.
Riande
, and
R.
Dı́az Calleja
,
J. Phys. Chem.
101
,
7324
(
1997
).
15.
(a)
G.
Fleischer
and
M.
Appel
,
Macromolecules
28
,
7281
(
1995
);
(b)
E.
von Meerwall
,
J.
Grisby
,
D.
Tomich
, and
R.
Van Antwerp
,
J. Polym. Sci., Polym. Phys. Ed.
20
,
1037
(
1982
).
16.
V. A.
Harmandaris
,
V. G.
Mavrantzas
, and
D. N.
Theodorou
,
Macromolecules
31
,
7934
(
1998
).
17.
G. D.
Smith
,
W.
Paul
,
M.
Monkenbusch
, and
D.
Richter
,
J. Chem. Phys.
114
,
4285
(
2001
).
18.
(a)
G. D.
Smith
,
D. Y.
Yoon
,
C. G.
Wade
,
D.
O’Leary
,
A.
Chen
, and
R. L.
Jaffe
,
J. Chem. Phys.
106
,
3798
(
1997
);
(b)
K. S.
Kostov
,
K. F.
Freed
,
E. B.
Webb
,
M.
Mondello
, and
G. S.
Grest
,
J. Chem. Phys.
108
,
9155
(
1998
).
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